The cpuidle_device->prepare() mechanism causes updates to thecpuidle_state[].flags, setting and clearing CPUIDLE_FLAG_IGNOREto tell the governor not to chose a state on a per-cpu basis atrun-time. State demotion is now handled by the driver and it returnsthe actual state entered. Hence, this mechanism is not required.Also this removes per-cpu flags from cpuidle_state enablingit to be made global.